Driveline Controller Terrain-Aware Reconnect Logic
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Solution Overview
Problem
Dynamic driveline systems in motor vehicles often experience slippage due to incorrect closure of clutch devices, leading to repeated reconnect operations, which can be triggered unnecessarily, especially on uneven terrain like sand, compromising vehicle progress and traction.
Innovation Solution
A controller that switches a releasable torque transmitting device between engaged and released conditions based on the speed disparity between axles and terrain type, preventing reconnect operations when adverse conditions, such as driving on sand, are detected, and suspending reconnects if powertrain torque exceeds a certain threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reconnect operations are performed repeatedly to ensure correct clutch closure, then reliability of torque transmission is improved, but vehicle progress is compromised and traction is lost
Solution Approach 1:
The controller performs preliminary assessment of terrain conditions before authorizing reconnect operations. By detecting whether the vehicle is traveling over sand or similar adverse terrain, the system prevents premature or inappropriate reconnect attempts that would compromise vehicle progress while ensuring reliable torque transmission only when conditions are favorable.
2Reliability
If reconnect operations are triggered based on wheel speed disparity, then correct clutch closure is achieved, but unnecessary reconnect operations are performed on uneven terrain
Solution Approach 1:
The controller continuously monitors multiple parameters including wheel speeds of first and second axles, terrain type, and powertrain torque output. This multi-parameter feedback mechanism allows the system to distinguish between genuine clutch closure failures (indicated by wheel speed disparity) and normal operational variations on uneven terrain, triggering reconnect operations only when truly necessary.
Solution Approach 2:
The system changes the decision parameters for reconnect operations from solely wheel speed disparity to a composite assessment including terrain type and powertrain torque. By modifying these control parameters, the system avoids unnecessary reconnect operations on sand or uneven terrain while maintaining reliable detection of actual clutch closure problems.
3Ease of operation
If the controller monitors terrain conditions and powertrain torque, then unnecessary reconnect operations are prevented, but device complexity increases
Solution Approach 1:
The controller leverages existing multi-functional sensors and processing capabilities already present in modern vehicles. Terrain detection uses existing wheel speed sensors and operational mode data, while powertrain torque monitoring utilizes the engine control unit's existing torque management functions. This approach adds terrain-aware reconnect control without requiring entirely new dedicated hardware systems.
Data Source
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AI summary
Embodiments of the present invention provide a motor vehicle controller comprising a computing device, the controller being configured to command a first releasable torque transmitting device of a driveline to switch between a released condition in which a first releasable torque transmitting device substantially prevents transmission of torque from an input to an output portion thereof, and an engaged condition in which a releasable torque transmitting device allows torque transmission from an input portion to an output portion thereof. The controller may be configured to receive information indicative of: a speed of wheels of a first axle; a speed of wheels of a second axle; and a terrain over which a vehicle is driving. The controller may be configured, in response to a detected disparity between the speed of wheels of said first and second axle when said first releasable torque transmitting device is switched to said engaged condition, in dependence upon said received information indicative of the terrain over which the vehicle is travelling, either: output a signal to automatically cause said first releasable torque transmitting device to perform a reconnect operation comprising momentarily resuming the released condition, and then subsequently resuming the engaged condition, or maintain said first releasable torque transmitting device in said engaged position.